Fla. sibling murder: "This is the stuff nightmares are made of"

GAINESVILLE, Fla. - A 15-year-old Florida girl accused of fatally shooting her 16-year-old brother had been locked in her room on different occasions with nothing but a blanket and a bucket to urinate in, Columbia County Sheriff Mark Hunter said during a Wednesday afternoon news conference.

"This is the stuff nightmares are made of," he added.

Two sisters, ages 15 and 11, are charged with premeditated murder for allegedly shooting their 16-year-old brother while he slept Monday evening. 48 Hours' Crimesider is not naming the family because of the young ages of the children involved.

According to Hunter, a 3-year-old child was also in the rural Columbia County home at the time of the shooting, but the children's parents were not.

Police say the investigation is ongoing and the motive has not been determined, however CBS affiliate WJAX reports the 15-year-old told police that her brother had beaten her and locked her in a bedroom. Police say the 11-year-old may have freed her sister from the room before the two allegedly exited the house and broke into their parents' locked bedroom via an exterior window. Inside the bedroom, the girls allegedly found and loaded a 9mm handgun.

The two then went back in the home, according to Hunter, and the eldest sister shot their 16-year-old brother.

Hunter said the 15-year-old girl admitted to police that she had killed her brother and during the course of the investigation, it was determined the 11-year-old assisted in the attack.

The children's parents have been arrested and charged with child neglect. Hunter said the neglect charges have nothing to do with the "immediate incident," and instead stem from other factors, such as the condition of the home and occasions where they had allegedly locked their eldest daughter in her room on several occasions with nothing but a blanket and a bucket to urinate in.

Hunter said the parents had had some issues with their 15-year-old daughter and had removed her from school at one point.

"This was their way of dealing with the child," Hunter said.

"This is a really, really sad case," the sheriff continued, adding, "I've never seen anything like this."

Police say they had been to the family's residence on three previous occasions for reports of property damage, a civil matter and a juvenile issue, which Hunter said was turned over to DCF and was "unfounded."

The two girls appeared in court Wednesday for a detention hearing and were ordered detained for the next 30 days, during which time the state attorney will make a determination as to whether they will be charged as juveniles or adults. One of the girls is being held in a detention center in Ocala while the other is being held in Gainesville.

The girls' parents are being held on $20,000 bond.